I am going to be adapting this setup for longer walks and in different environments, but the Fly Creek UL 2 with both layers worked great on a fairly exposed sand dune, directly facing the Southern ocean. The included pegs were stable in the sand.

A small 25L daypack can hold:

Enough food and water for around 48 hours

Sleeping bag

Tent

Stove

Pillow

Towel

Change of clothes

Full frame camera

Full frame wide angle lens

Stable tripod

iPad

Additional weight can be reduced by:

Using the tent in fast-fly mode - saves 0.4 kg

Swapping the tripod for a lighter solution - saves up to 0.4 kg

Swapping the A7s for an A6000 series camera body - saves 0.16 kg

Swapping the Zeiss Loxia 21mm for a different lens - saves up to 0.2 kg